This book teaches what every Christian, as a child of God, should believe and how every Christian, as a child of God, should live. The word "catechism" means instruction. This little book instructs in such a short and simple manner that even a child can easily understand. Dr. Martin Luther, the great Reformer of the Church, published this book to benefit the adults and the children who are most in need of such teaching. Luther doesn't write his own views and principles but the words of God for the betterment of humans. It does not teach all the doctrines of God's Word, but those that every Christian must know to believe rightly and lead a religious life in a short form, using plain and straightforward words.